Confirmed positive cases are matched to ONS geographical area codes using the the primary address postocde of the person tested. When the results are reported to PHE, they may contain more than one address, but the primary address used to link a case to a local authority is the address available in the centrally stored NHS Summary Care Record. In 92% of cases, for which both addresses area vailable, the primary address is within the same local authority as the alternate address. However, students pose a challenge to the established approach, as they may take some time to register with a General Practitioner (GP) in their university location if they do so, and therefore their registered GP address may not reflect where they are currently living. Some cases cannot be matched to a geographical area because postcode information is missing or received late. This is why the Local authority and Region counts do not add up to the England total.

Cases are attributed to the day they were reported to PHE.